A sound apparatus that forms a sound field by a synthetic sound image by using a plurality of loudspeakers has been known. For example, there is an audio source in which multi-channel audio signals such as 5.1 channels are recorded, such as a DVD (Digital Versatile Disc). A sound system that reproduces such an audio source has been widely used even in general households. In reproduction of the multi-channel audio source, if each loudspeaker is arranged at a recommended position in a listening room and a user listens at a preset reference position, a sound reproduction effect such as a surround effect can be acquired.
The sound reproduction effect is based on the premise that a plurality of loudspeakers are arranged at recommended positions, and the user listens at a reference position. Therefore, if the user listens at a position different from the reference position, the desired sound reproduction effect cannot be acquired. Patent Document 1 discloses a technique of correcting an audio signal so that a desired sound effect can be acquired, based on position information of a position where the user listens.